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| Home > Publications database > Analytical techniques for the determination of spallation products in a tantalum target |
| Home > Publications database > Analytical techniques for the determination of spallation products in a tantalum target |
| Book/Report | FZJ-2019-01612 |
1996
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag
Jülich
Please use a persistent id in citations: http://hdl.handle.net/2128/21711
Report No.: Juel-3282
Abstract: In a tantalum target used in the Spallation Neutron Souree ISIS of the Rutherford Appleton Laboratory the spallation products are to be determined in order to obtain a reliable data basis for the calculation of spallation yields by appropriate computer programs. These calculations are required tor the construction of targets for other spallation neutron sourees, especially the European Spallation Souree (ESS), for the planning of wh ich a project has been started at the Research Center Jülich. Nuclide specitic detection methods such as mass spectrometry and nuclear counting techniques are suitable for the determination of the spallation products. This report attempts to identify which techniques of chemical analysis available at the Research Center-Jülich can be used, wh ich spallation products can be determined by them and for which methods developments, improvements and adaptations will be necessary. An important role is played by chemical separation techniques, because most of the counting and measurement techniques cannot be applied directly to solid sampies taken from the target. For most spallation products well-tried separation procedures are not yet available and have to be developed with special respect to the conditions of the highly radioactive tantalum matrix. Thestable nuclides in the spallation products, which represent the majority, can probably be measured by the "ELEMENT" mass spectrometer in operation at the Central Department of Analytical Chemistry (ZCH), which has a good mass resolution and very low limits of determination. Developmental work is in progress with this instrument for on-line separation procedures by HPLC for some of the most interesting spallation products. Gamma-ray spectrometers are readily available including procedures tor the evaluation of the spectra, but some developmental work is necessary to include the many neutron deficient radionuclides in the nuclide catalogue required for the automatie identification of the radionuclides by the computer program used for interpretation of the spectra. The next rank in the measurement methods is occupied by liquid scintillation counting. It is suitable for those nuclides emitting only ß-rays or low-energy X-rays and atomic electrons. In every case, the radionuclides must be separated and highly purified before this counting technique can be applied. Low-energy photon spectrometry might also be useful but is not readily available at the ZCH. Alpha-spectrometry is required for only a few nuclides and might possibly be carried out with sampies from aseparated fraction containing only the heavy rare earth elements. Neutron activation analysis will be used in the analysis of "background material", i.e. of parts from the edges of the target distant from the primary proton beam and practicallynot exposed to the spallation process, if such parts can be found. Neutron activated samples of tantalum will also be used in the development of separation procedures for the chemical elements to which spallation products belong, because many of the impurities present in tantalum yield neutron activation products and most of them can also be found as radioactive spallation products in the target.
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